1. Field of Invention
The present invention relates to a printed circuit board (PCB) antenna, and more particularly to a dual-frequency high-gain antenna.
2. Related Art
Along with the development of wireless communication technology, information can be transmitted by a wireless communication system without the limitation of geography. Being one of the most important elements in the wireless communication field, the current antenna is preferably fabricated by means of PCB with various advantages such as being simple and low in cost.
At present, the standard of wireless transmission is constituted by the Institute of Electrical and Electronics Engineers (IEEE), so as to make the wireless transmission technology widely utilized, and ensure that the devices produced by various manufacturers are compatible and stable.
In an ordinary radio-frequency circuit, passive parts are frequently used, such as antenna, diplexer, high low band stop filter, balun, power divider and coupler, wherein the antenna is an important element that has impact on the signal transmission quality. With the co-existence of the 2.4 GHz frequency band and 5 GHz frequency band on a communication chip, the antenna must simultaneously receive frequencies of the two frequency bands. However, in general, the dual-frequency antenna has the disadvantages of being insufficient in bandwidth and gain and has the problem of being difficult to integrate.
Therefore, how to provide a dual-frequency high-gain antenna to improve the signal transmission bandwidth thereof has become a problem to be settled by the researchers.